Identification of hyperelastic properties of CMR patient-specific left ventricle by finite elements and virtual fields method

Abstract

Detection of left ventricle (LV) myocardial dysfunction after doxorubicin-based chemotherapy is investigated by determining myocardial stiffness, which is a potential clinical biomarker for the monitoring of heart failure (HF). The combination of cardiac magnetic resonance (CMR) imaging and the finite element method (FEM) was used to estimate anisotropic elastic stiffness in the LV. The myocardium also has a complex geometry with nonlinear hyperelastic properties leading to large deformation. Within the proposed framework, which generates the LV mesh and reconstructs the strain field from the existing CMR data, we apply the virtual field method (VFM) to determine the hyperelastic material parameters. Minimizing an energy-based objective function obtained from VFM identifies the unknown parameters coupled in nonlinear constitutive law considering passive myocardial behavior. While Full-field characterization using VFM is valuable for studying regular-shaped models, we propose applying this method when particularly looking into ventricular remodeling caused by doxorubicin, in the context of cardiotoxicity. In the cardiac diastolic phase, the estimated stiffness of VFM results with FEM validation is compared for a case study of leukemia cancer survivors separated into three groups.